Abstract Lithiated bis (diphenylphosphino) methane reacts with two equivalents of a dialkylchloro-alane or-gallane (R 2 MCl; R= CH 3, C 2 H 5; M= Al, Ga;) to form coordination compounds (3–6) which have peculiar structure and show unusual fluxional behaviour. A single crystal X-ray diffraction study of the compound ((C 6 H 5) 2 P] 2 CH [(C 2 H 5) 2 Al] 2 Cl (4) reveals that these complexes can be described as the unsymmetrical adducts of the ...